Manuel Almunia has responded to speculation about his future at Arsenal by insisting he does not have to "convince anybody" of his credentials as a goalkeeper.

It is expected Arsène Wenger will add another goalkeeper to his squad before the start of the Premier League season, with Mark Schwarzer believed to be his principal target.

Fulham have rejected a £2m bid for the 37-year-old but the player is keen on a move to the Emirates and is expected to relay that view to Mark Hughes after he is presented as the Fulham manager at a press conference today.

Schwarzer's arrival would threaten Alumina's place in the Arsenal team. The Spaniard established himself as Wenger's No1 following the departure of Jens Lehmann in June 2008 but has failed to fully convince and last season was forced to fight for his position with Lukasz Fabianski. Almunia played 36 times, keeping 13 clean sheets, while Fabianski featured in 10 matches and kept two clean sheets.

The pair have shared goalkeeping responsibilities during Arsenal's pre-season programme, with Almunia playing twice, including in Sunday's 3-2 Emirates Cup win over Celtic, and Fabianski three times.

Such switching points to a lack of faith in the pair by Wenger but Almunia is not worried. "I don't need to convince anybody – I just do my job," the 33-year-old said. "I have a couple more years on my contract and that's it, I'm an Arsenal player."

Whoever ends up in goal will want greater cover from their defence than was the case last season. Arsenal conceded 41 goals during the Premier League campaign, nine more than champions Chelsea and six more than Liverpool, who finished four places below them in seventh.

Arsenal's defensive frailties were again apparent during the Emirates Cup, when they allowed Milan to equalise through a weak header from Pato and conceded two late and avoidable goals to Celtic.

The French full-back Bacary Sagna admits such sloppiness is a worry and has called on his fellow defenders – which is likely to include the addition of one more centre-back – to cut out such errors before the opening game of the new season, which is away to Liverpool on 15 August.

"We definitely need to be more consistent," Sagna said. "If you remember what happened last year against Wigan [when Arsenal lost 3-2 having led 2-0], that shows we need to keep playing [until the end of the game]. Maybe we stop playing sometimes because we think the game is too easy. We need to talk more on the pitch and stay together."

Overall, however, Sagna is in positive mood, having been part of a team who have won four and drawn one of their five summer fixtures so far and seen the encouraging debuts of new recruits Laurent Koscielny and Marouane Chamakh.

Chamakh, who arrived on a free transfer from Bordeaux in May, has impressed Sagna with two goals, so much so he believes the 26-year-old can have a similar impact for Arsenal as Emmanuel Adebayor did prior to his move to Manchester City last summer.

"He [Chamakh] can make the difference because he is a good player, can keep the ball and score great goals," Sagna said. "It will be very important to have a player like that in front of goal. I will trust him with the ball because he can keep it quite easily. He looks like Adebayor – they are both very good in front of goal and that is a good thing for the team."